Stationary steam engines, simple and compound; especially as adapted to light and power plants . XCIII. STEAM ENGINES FOR and tandem. The valves are on one rod, driven by asingle eccentric on the crank-pin ; the rod being in the axis of the engine and thevalves within the hollowpiston-rod. Cut-off is ef-fected by the passage of theports into metallic rings inthe ends of the cylinders,and is adjustable by hand orby the governor. Compres-sion is effected in the sepa-rate cushion-chamber.^ These engines are usuallygrouped in pairs, with cranksat right angles. As the valve-faces movewith the pisto
Stationary steam engines, simple and compound; especially as adapted to light and power plants . XCIII. STEAM ENGINES FOR and tandem. The valves are on one rod, driven by asingle eccentric on the crank-pin ; the rod being in the axis of the engine and thevalves within the hollowpiston-rod. Cut-off is ef-fected by the passage of theports into metallic rings inthe ends of the cylinders,and is adjustable by hand orby the governor. Compres-sion is effected in the sepa-rate cushion-chamber.^ These engines are usuallygrouped in pairs, with cranksat right angles. As the valve-faces movewith the pistons, the valve-motion must here be takenfrom the pins to secure thedesired movement relativelyto the pistons. The work onthe main journals and pins issubstantially all on the upper brass of the latter and theWiLLANs Engine. (Scale ^V-) j^^^g, ^f the former, and the crank-pin working-side is never expected to leave the eccentric-rod, like the connecting-rod, is always in com-pression, and the main bearings also are always under con-stant downward thrust. Lubrication is secured, by the. 1. Trans. Brit. Inst. C. E., Vol. LXXXI. p. i66. ELECTRIC LIGHTING PLANTS. Westinghouse method, by the dipping of the crank into apool of oil and water in the crank-case. The guide-pistonsare arranged to produce the needed cushion by compressionof the air in the compression-chambers, and this is adjustableas may prove to be advisable. The governor is of the nowfamiliar Hartnell type. Multiple-cylinder diagrams take forms as follow :In this illustration from Mr. Porters report the naturalform of the expansion-line in the single cylinder havingthe capacity here observed in the low-pressure engine,would be that shown by one or other of the two dottedlines, accordingly as the expansion approaches more or lessclosely the hyperbolic form. The initial volume is ABand the pressure as shown on the vertical scale, while thegradual loss of pressure with increase of volume is shown bythe two scales as
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectsteamen, bookyear1902
